In xerographic or electrophotographic copier machines, a photoconductive member is charged to a substantially uniform potential to synthesize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being copied or reproduced. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document. The latent image is then developed by bringing a developer material, usually powdered toner particles adhering triboelectrically to carrier granules, into contact therewith. The toner particles are attracted to the latent image from the carrier granules to form a powder image on the photoconductive member which is subsequently transferred to a copy sheet. Finally, the copy sheet is heated to permanently affix the powder image thereto in image configuration.
The developer material is brought into contact with the electrostatic latent image on the photoconductive member in a development system or station within such xerographic copier machine and such system or station utilizes rollers having outside electrically-conductive surfaces thereon for transporting and applying the developer material. These rollers often include elongated magnets positioned concentrically within the rollers and a voltage source attached thereto which electrically biases the rollers to a selected magnitude and polarity intermediate that of the background voltage and image voltage level recorded on the photoconductive member. These rollers are utilized in the development system as both transporting rollers for transporting the developer material through the development system or station and as applying rollers for applying the toner particles in the developer material to the electrostatic latent image on the photoconductive member as it passes by such applying rollers. Those rollers utilized in the development system as applying rollers usually include spaced-apart grooves in the outside surface of each of the rollers which extend longitudinally of the roller and cover the entire circumference of the roller for ensuring an even distribution of developer material along the roller for applying the toner particles to the electrostatic latent image on the photoconductive member.
Heretofore, these rollers, utilized in development systems of xerographic copier machines, have been for the most part constructed of solid aluminum or stainless steel. When such rollers begin to malfunction for their desired purpose in the xerographic copier machine operation, such rollers had to be removed from the machines, cleaned or otherwise replaced in the machines. This, as can be appreciated, was an expensive procedure due to the cost of solid aluminum or stainless steel rollers.